Lab 1 Prelab Assignment F2023

docx

School

University of Texas, Arlington *

*We aren’t endorsed by this school

Course

339

Subject

Mechanical Engineering

Date

Oct 30, 2023

Type

docx

Pages

Uploaded by pugsnotdrugs3000

Name (print): Section (day/time): ME139L-Experimental Heat Transfer Lab #1 Pre-Lab Preparation (Due before the lab meeting for Lab #1) Background Information For Lab #1, you will learn how to measure temperature using a variety of devices including thermocouples, resistance temperature detectors, and thermistors. It is important to understand how these devices operate as well as their characteristics and their advantages or disadvantages as a temperature sensor. These topics are the focus of this pre-lab exercise. Assignment 1. Read the file entitled "Practical Guidelines for Temperature Measurements" which is posted together with this pre-lab assignment in the Lab 1 folder of the Lab Documents folder on the Canvas website. Also, browse through the file entitled “Practical Temperature Measurements ” which is also located in this folder. These files are part of a larger body of information that is available on the Omega Engineering website at Omega.com or from a variety of other web-based sources. 2. Fill out the tables on the second page of this handout. You need to go to the references already provided in the table to gather the information. The Type K thermocouple is presented as a simple example of what is required. Please be thorough and complete in your work. 3. The resolutions and accuracies for both meters when using different devices (Thermocouple, RTD, and Thermistor) have been provided on the third page. Please give the details of your calculation procedure. An example for Supermeter/K-type TC has been shown. Ref. No. Source 1 Omega Engineering. "Practical Guidelines for Temperature Measurement", pp. Z-13- Z-15 (from “Omega Reference Materials.pdf”) 2 Omega Engineering, "Practical Temperature Measurements", pp. Z-19-Z-56 (from “Omega Reference Materials.pdf”) 3 Omega Engineering, “Revised Thermocouple Reference Tables,” (“Type K Thermocouple Tables.pdf”) 4 Omega Engineering, “Revised Thermocouple Reference Tables,” (from “Type E Thermocouple Tables.pdf”) 5 Omega Engineering, “RTD Temperature vs. Resistance Table,” pp. Z-252-Z-254 (from “RTD Tables.pdf”) 6 Omega Engineering, “Thermistor Resistance vs. Temperature,” pp. Z-256-Z-257 (from “Thermistor Tables.pdf”)

Name (print): Section (day/time): Based on the sources provided, fill in the information in the table below. Information for the Type-K thermocouple is given as an example. Sensor characteristic Thermocouple Type K Thermocouple Type E Resistance temperature detector (RTD) Thermistor Omega 44004 Principle of operation Junction of two different metals creates a small measurable voltage (emf) proportional to temperature (Ref 2, p. Z-21) (Ref 2, p. Z-21) (Ref. 1, p. Z-13) (Ref. 1, p. Z-13) Materials of construction Nickel-10% Chromium and Nickel (Ref. 2, p. Z-40) (Ref. 2, p. Z-40) (Ref. 2, p. Z-34) (Ref. 2, p. Z-36) Output (voltage, current, resistance?) Voltage (mV or  V) (Ref. 2, p. Z-25,26) (Ref. 2, p. Z-25,26) (Ref. 2, p. Z-34) (Ref. 2, p. Z-37) Typical service temperature range -270-1372  C (Ref. 2, p. Z-40) (Ref. 2, p. Z-40) (Ref. 1, p Z-15) (Ref. 1, p. Z-15) Typical sensor accuracy (  C) ± 2.2°C below 277°C ± 3/4% of reading 277-1260°C ± 9.5°C above 1260°C (Ref. 2, p Z-39) (Ref. 2, p Z-39) (Ref. 2, p. Z-55) (Ref. 6) Sources of sensor error Changes in alloy composition; mat’l inconsistencies leading to instability (Ref. 2, p. Z-39) (Ref. 2, p. Z-39) (Ref. 2, p. Z-55) (Ref. 2, p. Z-37) Resolution (  C) if meter resolution is 0.01 mV or 0.01  = 0.01 mV/0.04096 mV/ o C = 0.24°C(for S = 0.04096 mV/ o C) (S calculated based on Ref. 3 for range of 0 o C-100 o C) (Ref. 4 for range of 0 o C-100 o C) (Ref. 5 for range of 0 o C-100 o C) (Ref. 6 for range of 0 o C-100 o C) Note: To calculate resolution, use the instrument sensitivity based on change in voltage or resistance from 0-100 o C as shown in lecture notes.

Name (print): Section (day/time): Signal conditioning/readout devices Any transducer that produces an electrical signal requires a signal conditioning and display system. We will use two such systems, an Omega "Supermeter" (price  $250) and a Keithley 2700 6 1/2 digit multimeter/data acquisition unit (price  $2500). From their respective spec sheets, determine the resolution and accuracy of each of these instruments. Assume that you are measuring the temperature of water at nominally 60 o C with a K-type thermocouple (TC), an RTD, and a thermistor. Use the thermocouple, RTD, and thermistor tables to determine what voltage and resistances correspond to 60 o C . Meter Resolution (mV) K-Type TC Accuracy (mV) K-Type TC Resolution (  RTD Accuracy (  RTD Resolution (  Thermistor Accuracy (  Thermistor Supermeter 0.01 mV 0.015 mV Keithley References you may need: Omega Supermeter Manual.pdf Omega Supermeter Spec.pdf Keithley 2700 MM Brochure.pdf Keithley 2700 MM Spec.pdf Type K Thermocouple/RTD/Thermistor Tables.pdf Example for Supermeter/K-type TC: 60 o C  2.046 mV for K-type thermocouple from “Type K ThermocoupleTables.pdf” 2.046 mV  Best-fit range 0-4.3 based on “Omega Supermeter Spec.pdf”  the display resolution 0.0001 However, if you check the voltage range in the second column of the same table, you will see the minimum range for voltage is 430 mV (saying 430 mV to 1000 V in the table). Thus, we have to use the range 0-430: 2.046mV  0-430  0.01 mV for the display resolution. Then, 0.25% Rdg + 1 Digit for accuracy (from the same table): Accuracy (mV) = (0.0025)(2.046 mV) + (1)(0.01 mV) = 0.015 mV Your calculations for all other values in the table are expected.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version